Luigia Gozzini

Gadobenate dimeglumine 0.5 M solution for injection (MultiHance) pharmaceutical formulation and physicochemical properties of a new magnetic resonance imaging contrast medium.

OBJECTIVE To characterize the proton-magnetic relaxation properties and complexation equilibria of gadobenate dimeglumine and to develop a pharmaceutical formulation for injection. METHODS Proton-magnetic relaxivities were determined at 20 MHz and 39 degrees C. Metal complexation was studied potentiometrically. Degradation pathways were identified through prolonged exposure to elevated temperature. RESULTS Because of its size and very weak interaction with serum albumin, gadobenate dimeglumine has proton-magnetic relaxivities that are larger than those of gadopentetate dimeglumine in both water and biological fluids. With regard to metal complexation, the two products are indistinguishable. The metal complexation behavior and thermal stability of the product allowed a pharmaceutical formulation for injection containing 0.5 M gadobenate dimeglumine without excipients. The physicochemical properties of the formulated product were determined. CONCLUSION Gadobenate dimeglumine has an elevated T1-relaxivity, especially in blood plasma. The high stability of the complex guarantees a negligible release of gadolinium ion. Gadobenate dimeglumine 0.5 M solution for injection has a shelf life of three years.

Taxonomic Lactobacillus Composition of Feces from Human Newborns during the First Few Days

A bstractIntestinal microbiota comprise a complex ecosystem whose equilibrium is crucial for the health of animal species. For humans, data exist on the microbiota composition in adult subjects, but few studies have addressed the microbiota composition in infants. In particular, data on the presence and species distribution of members of the genus Lactobacillus in newborns (less than one week old) are lacking. In the present work, the feces of healthy newborns were sampled to determine the taxonomic composition of Lactobacillus in the intestinal microbiota in a group of 16 neonates. In total, 1640 colony-forming units (CFU) were isolated, of which 420 grouped in the Lactobacillus genus by means of primary phenotypic characterization. The 420 isolates were further grouped into 125 strains on the basis of identical plasmid profiles. Of these 125 strains, 21 turned out to be permanent, i.e., they were identified in the feces of the same subject on several consecutive days. Sugar fermentation, DNA/DNA hybridization, and S-layer protein determination enabled us to classify 52 of the 125 strains as follows: L. paracasei (40 strains), L. delbrueckii sp. (1 strain), and L. acidophilus (sensu stricto) (11 strains). Based on the same criteria, the remaining 73 strains were tentatively allotted to the Johnson subgroup B, although hybridization experiments with probes specific for L. gasseri and L. johnsonii species were not performed. The presence of new species among these 73 strains cannot be excluded. Surprisingly, the obligately heterofermentative lactobacilli, L. reuteri in particular, were entirely absent from the feces of healthy newborns.